Home and business alarms have become commonplace. Such alarms (often referred to as “security systems” or “alarm systems”) typically include several sensors used to monitor unauthorized entry and other conditions at monitored premises, such as fire, smoke, toxic gases, high/low temperature (e.g. freezing) or flooding, at a premises. In response to sensing an alarm condition, a sensor provides a signal to an alarm panel that in turn may sound and notify the occurrence of the alarm to occupants of the premises and remotely signal a monitoring station or other third party.
Typically the occurrence of an alarm is signalled to a remote monitoring station that may then dispatch capable authorities to intervene at the premises. For example, in the case of sensing an unauthorized entry to the premises, the monitoring station may dispatch security personnel, typically in the form of private security guards or police officers. Such communication between the premises and the monitoring station has typically taken place by way of the public switched telephone network (PSTN).
With the desire for greater security and the advent of other communication networks more modern alarm systems utilize such other networks either in addition to or in place of the PSTN. In particular, the use of wireless (cellular) networks has become fashionable in the event that the connection to the PSTN is severed or is otherwise unavailable.
Conveniently, as the alarm system acts as a connection point to the PSTN for the entire premises, the cellular networks may act as a back-up, not only for alarm system calls, but also for conventional outgoing PSTN calls placed from the premises. That is, in the event of failure of the PSTN, conventional voice calls may be bridged to the wireless network through the alarm system.
Unfortunately, use of wireless networks is costly. Moreover, cellular network operators often levy charges in dependence on whether a data or voice call is placed using the cellular network.
Accordingly there is a need for alarm systems, network interfaces and methods that may make cost-efficient use of such networks.